Analysis of drum brake squeal
Loading...
Date
2015-06-01
Authors
Muhammad Najib Abdul Hamid
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The operational deflection shapes were used to identify the mode of vibration for the brake shoes in drum brake squeal. The measurement of the operational deflection shapes of the brake shoes during drum brake squeal, which was in the torsional mode, was similar to that of the modes obtained from the experimental modal analysis of the brake shoe under the in-contact static condition. A two-degree-of-freedom model was developed on the basis of the experimental modal analysis data within the limited bandwidth of the squeal frequency of 1850 Hz. In this work, the operational deflection shape was used for determination of a structural dynamic modification to be carried out on the brake shoes in order to maximize the damping of the torsional mode as a way to improve the stability of the system. The lumped parameter model was then used to assess the effect of the structural dynamic modification on the squeal based on the transient analysis, which showed a similar trend and can assist brake designers in evaluating the critical parameter to obtain a squeal-free drum brake design. The drum brake squeal was further analysed using finite element method. The second part of this study was the dynamic instability of a drum brake system, which consists of a rotating drum and two immobile brake shoes which took into consideration the rotation effect on the complex eigenvalue. The Coriolis force and the centrifugal load represented the effect of the rotation of the drum. The results indicated an unstable mode at 1658 Hz, which is equivalent to the measured frequency of the drum brake squeal. As the speed was increased, the positive real part of the complex eigenvalue Re(λ) decreased and became negative at speeds beyond 600 rpm.